The invention relates to a melting furnace or the like, in a design of a steel structure with a refractory lining.
The invention was developed as a consequence of problems arising in connection with melting furnaces for aluminium, and other materials. Such melting furnaces are at present made from common steel which is lined with refractory material.
A typical melting furnace has a length of approximately 8 m, a width of approximately 5 m, and a height of approximately 1.5 m. Such melting furnaces are welded from common sheet material St. (DIN) 42, or St. (DIN) 52-3. The furnaces are provided with an internal lining of a refractory material.
The weight of aluminium and the refractory lining carried by the furnace amounts to 50-80 tons. The load of aluminium and the lining is received by the steel structure of the furnace, which is thus subjected to high bending loads. During operations, the steel material of the furnace is subjected to high temperature loads. Temperatures will vary from approximately 200.degree. C. to 400.degree. C. Over time, the insulating lining will be impaired, and the steel material is sujected to an increased heat load. The structure, as mentioned, being produced from common steel material, which will lose its stability at approximately 200.degree. C., will sag and become lopsided, resulting in fracturing and destruction of the refractory lining material.
If it were possible to prevent the furnace from losing its shape, the life of the furnace and its lining could be prolonged. This would result in fewer interruptions for replacements of furnaces, and reduced costs for mending and renovating the furnaces.